Do not use CXXZeroValueInitExpr for class types. Instead, use

CXXConstructExpr/CXXTemporaryObjectExpr/CXXNewExpr as
appropriate. Fixes PR7556, and provides a slide codegen improvement
when copy-initializing a POD class type from a value-initialized
temporary. Previously, we weren't eliding the copy.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107827 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 15 insertions, 30 deletions

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 2c631064ef..3619193434 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -480,7 +480,7 @@ bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *&E) {
 
   MarkDeclarationReferenced(E->getExprLoc(), Destructor);
   CheckDestructorAccess(E->getExprLoc(), Destructor,
-                        PDiag(diag::err_access_dtor_temp) << Ty);
+                        PDiag(diag::err_access_dtor_exception) << Ty);
   return false;
 }
 
@@ -566,27 +566,19 @@ Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep,
                                                      RParenLoc));
   }
 
-  if (const RecordType *RT = Ty->getAs<RecordType>()) {
-    CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
-
-    if (NumExprs > 1 || !Record->hasTrivialConstructor() ||
-        !Record->hasTrivialDestructor()) {
-      InitializedEntity Entity = InitializedEntity::InitializeTemporary(Ty);
-      InitializationKind Kind
-        = NumExprs ? InitializationKind::CreateDirect(TypeRange.getBegin(), 
-                                                      LParenLoc, RParenLoc)
-                   : InitializationKind::CreateValue(TypeRange.getBegin(), 
-                                                     LParenLoc, RParenLoc);
-      InitializationSequence InitSeq(*this, Entity, Kind, Exprs, NumExprs);
-      OwningExprResult Result = InitSeq.Perform(*this, Entity, Kind,
-                                                move(exprs));
-
-      // FIXME: Improve AST representation?
-      return move(Result);
-    }
-
-    // Fall through to value-initialize an object of class type that
-    // doesn't have a user-declared default constructor.
+  if (Ty->isRecordType()) {
+    InitializedEntity Entity = InitializedEntity::InitializeTemporary(Ty);
+    InitializationKind Kind
+      = NumExprs ? InitializationKind::CreateDirect(TypeRange.getBegin(), 
+                                                    LParenLoc, RParenLoc)
+                 : InitializationKind::CreateValue(TypeRange.getBegin(), 
+                                                   LParenLoc, RParenLoc);
+    InitializationSequence InitSeq(*this, Entity, Kind, Exprs, NumExprs);
+    OwningExprResult Result = InitSeq.Perform(*this, Entity, Kind,
+                                              move(exprs));
+
+    // FIXME: Improve AST representation?
+    return move(Result);
   }
 
   // C++ [expr.type.conv]p1:
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 536222c37f..6b7ff63372 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -2772,8 +2772,7 @@ static void TryValueInitialization(Sema &S,
       //    zero-initialized and, if T’s implicitly-declared default
       //    constructor is non-trivial, that constructor is called.
       if ((ClassDecl->getTagKind() == TTK_Class ||
-           ClassDecl->getTagKind() == TTK_Struct) &&
-          !ClassDecl->hasTrivialConstructor()) {
+           ClassDecl->getTagKind() == TTK_Struct)) {
         Sequence.AddZeroInitializationStep(Entity.getType());
         return TryConstructorInitialization(S, Entity, Kind, 0, 0, T, Sequence);        
       }
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 1abcf205dd..9c8f48bfea 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -92,12 +92,6 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
   
   if (const CXXExprWithTemporaries *Temps = dyn_cast<CXXExprWithTemporaries>(E))
     E = Temps->getSubExpr();
-  if (const CXXZeroInitValueExpr *Zero = dyn_cast<CXXZeroInitValueExpr>(E)) {
-    if (const RecordType *RecordT = Zero->getType()->getAs<RecordType>())
-      if (CXXRecordDecl *RecordD = dyn_cast<CXXRecordDecl>(RecordT->getDecl()))
-        if (!RecordD->hasTrivialDestructor())
-          return;
-  }
       
   if (const CallExpr *CE = dyn_cast<CallExpr>(E)) {
     if (E->getType()->isVoidType())